<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .wrap{
            width: 900px;
            height: 500px;
            background-color: #ccc;
        }
        .box1{
            width: 300px;
            height: 300px;
            background-color:green;
            float: left;
            /* float: right; */
        }
        .box2{
            width: 250px;
            height: 250px;
            background-color: red;
            float: left;
        }
        .box3{
            
        }
    </style>
</head>
<body>
    <div class="wrap">
        <div class="box1">box1盒子</div>
        <div class="box2">box2盒子</div>
        <div class="box3">box3</div>
    </div>
</body>
</html>